When optical components are used, their arrangement in the beam path can be of great importance. In this case, it is possible to differentiate between a positioning in the direction of the beam path and a position perpendicular thereto. Depending on the application, one or the other or both of these positions may be of great importance.
By way of example, for the arrangement of filters and/or stops, the precise positioning thereof in the direction perpendicular to the beam path is often of great importance.
An obscuration stop is known for example from WO 2006/069 725 A1 and DE 10 2010 040 108 A1.